Usage of i2c_-Tools in Barebox

Hi,

i'm using a phyFLEX-i.MX6 SBC and want to communicate with an external µC over I2C. I only want to read/set 1 register, so i tried to use the builtin i2c_read and i2c_write-Commands. The µC is connected to i2c-bus 1 of the device, so i tried to probe the hole bus with "i2c_bus 1 3 30". The command only answered with "i2c_probe: No such device". I tried also the busses 0-3, with the same result. I searched in the board.c sourcecode of the phyflex, but couldn't find i2c related stuff, so i think, i have to add the initalisation for the i2c.

Do i have to add the i2c-init in the boards/phytec-pfla02/board.c -file? Is there some documenation about this stuff?

Quoted 10 lines · Marcel Behlau

i'm using a phyFLEX-i.MX6 SBC and want to communicate with an external µC over I2C. I only want to read/set 1 register, so i tried to use the builtin i2c_read and i2c_write-Commands. The µC is connected to i2c-bus 1 of the device, so i tried to probe the hole bus with "i2c_bus 1 3 30". The command only answered with "i2c_probe: No such device". I tried also the busses 0-3, with the same result. I searched in the board.c sourcecode of the phyflex, but couldn't find i2c related stuff, so i think, i have to add the initalisation for the i2c.

Quoted 2 lines

Do i have to add the i2c-init in the boards/phytec-pfla02/board.c -file? Is there some documenation about this stuff?

The phyFLEX board is device tree based. You have to enable the i2c controller in the dts file (same as you would do in the kernel). Usually a:

&i2c0 {
	status = "okay";
};

Should be enough. You probably also have to add the proper pinctrl node.

Hello,

Quoted 17 lines · Sascha Hauer

Quoted 10 lines · Marcel Behlau

i'm using a phyFLEX-i.MX6 SBC and want to communicate with an external µC over I2C. I only want to read/set 1 register, so i tried to use the builtin i2c_read and i2c_write-Commands. The µC is connected to i2c-bus 1 of the device, so i tried to probe the hole bus with "i2c_bus 1 3 30". The command only answered with "i2c_probe: No such device". I tried also the busses 0-3, with the same result. I searched in the board.c sourcecode of the phyflex, but couldn't find i2c related stuff, so i think, i have to add the initalisation for the i2c.

Quoted 2 lines

Do i have to add the i2c-init in the boards/phytec-pfla02/board.c -file? Is there some documenation about this stuff?

The phyFLEX board is device tree based. You have to enable the i2c controller in the dts file (same as you would do in the kernel). Usually a:

Quoted 5 lines

&i2c0 {
	status = "okay";
};

Should be enough. You probably also have to add the proper pinctrl node.

and enable the i2c driver. You might want to check the output of devinfo.

Best regards
Uwe

Hi,

many thanks for your help. I activated the i2c devices in the device tree, the pinctrl is already done in the imx6q.dtsi, which is included. The used pins are identically with the used pins on the SBC. devinfo told me, that the driver "i2c-fsl" is loaded. After rebuild barebox, it's possible to probe the bus, but the command only answered with an timeout:

barebox@Phytec phyFLEX-i.MX6 Quad Carrier-Board:/ i2c_probe 1 83 83 probing i2c range 0x53 - 0x53 :
i2c2: <i2c_fsl_bus_busy> timeout waiting for I2C bus busy

Quoted 9 lines · Marcel Behlau

Hi,

many thanks for your help. I activated the i2c devices in the device tree, the pinctrl is already done in the imx6q.dtsi, which is included. The used pins are identically with the used pins on the SBC. devinfo told me, that the driver "i2c-fsl" is loaded. After rebuild barebox, it's possible to probe the bus, but the command only answered with an timeout:

Quoted 3 lines

barebox@Phytec phyFLEX-i.MX6 Quad Carrier-Board:/ i2c_probe 1 83 83 probing i2c range 0x53 - 0x53 :
i2c2: <i2c_fsl_bus_busy> timeout waiting for I2C bus busy

I *think* this means that the levels on the bus do not properly follow what the controller wants to do. Maybe pullup missing? An oscilloscope might help here.

Sascha

Hi,

i found the problem. The Pad Mux Register (0x20E008C and 0x20E0090) are not initialised. In both registers is a 0x00000005 (reset value), instead of 0x00000016. I think, i must specify the value of the mux register in the device tree, too. How can i do this?